The invention relates to an exhaust system for a combustion engine, in which the engine may be either a four-stroke or a two-stroke petrol engine. The use of an exhaust system in two-stroke engines is especially advantageous, however. Because of its compact construction, this exhaust system may also be used in hand-operated tools, such as petrol-driven chainsaws, hedge trimmers or similar. The exhaust systems includes a housing in which at least one aperture is provided for an exhaust gas inlet, and a further aperture is provided for an exhaust gas outlet. To prevent the exhaust gases from escaping into the atmosphere without being cleaned, at least one catalytic element is also arranged in the housing, so that some or all of the exhaust gases flow through the catalytic element before they escape into the atmosphere through the gas outlet aperture.
It is known from the prior art to used catalytic elements in exhaust systems to reduce emissions of pollutants from combustion engines. These catalytic elements enable subsequent treatment of the exhaust gas with the components contained in the gas. The hydrocarbons are converted to carbon dioxide or carbon monoxide using the residual oxygen content. For lower conversion rates, i.e. if not all hydrocarbons are converted into carbon dioxide or carbon monoxide, coated metal meshes may be useful instead of the usual honeycomb catalytic converters. In a broader comparison with honeycomb catalytic converters, the production of 2-dimensional catalytic element is particularly simple and correspondingly cheaper.
In this context, the object of the invention was to provide an exhaust system having a catalytic element that may be manufactured easily and inexpensively but with which a high conversion rate may be achieved, to satisfy increasingly stringent environmental regulations.
This object is solve by the features listed in claim 1, which are particularly significant for the following reasons.